Among existing flat display technologies, a Liquid Crystal Display (hereinafter “LCD”) can be considered as one of the most mature technologies, for example, a mobile phone, all of a digital camera, a video camera, a notebook computer, a monitor, etc., as common in daily life are products manufactured with this technology. Among the LCD technologies, a Thin Film Transistor Liquid Crystal Display (hereinafter “TFT LCD”) is predominant at present in the LCD market due its characteristics of low power consumption and a relatively low fabrication cost as well as a superior transmittivity and aperture ratio.
As illustrated in FIG. 1 and FIG. 2, a Thin Film Transistor (hereinafter “TFT”) array substrate in the prior art includes a substrate 101, and a plurality of gate lines 102 and a plurality of data lines 103 arranged on the substrate 101, and the plurality of gate lines 102 intersect with the plurality of data lines 103 so that adjacent gate lines and data lines define a pixel unit, and each pixel unit includes a Thin Film Transistor (simply TFT below) 104 and a pixel electrode 105 electrically connected with a drain/source of the TFT, and the TFT is arranged at the intersection of a gate line 102 with a data line 103. Each TFT 104 includes a gate 106, an active layer 107, the source 108 and the drain 109. A first insulation layer 118 is arranged between the active layer 107 and the substrate 101, a second insulation layer 110 is arranged between the active layer 107 and the gate 106, a third insulation layer 111 is arranged between the gate 106, and the source 108 and the drain 109, the source 108 and the drain 109 are formed on the third insulation layer 111 respectively through a via 114 and a via 115, and a passivation layer 112 and a planarization layer 113 are arranged on the source 108 and the drain 109. Finally the pixel electrode 105 is deposited. The gate 106 is formed integral to the gate line 102, the source 108 and the drain 109 are formed with the data line 103 simultaneously, and the drain 109 and the pixel electrode 105 are typically connected through a passivation layer via 118. When a turn-on signal is applied to the gate line 102, the active layer 107 is electrically conductive, and a data signal of the data line 103 can reach the drain 109 from the source 108 through a channel of the active layer 107 and is then provided to the pixel electrode 105. The pixel electrode 105 receiving the signal forms with a common electrode (where the common electrode can be arranged on the array substrate or a color film substrate not illustrated dependent upon the type of display panel) an electric field causing liquid crystals to rotate.
A storage capacitor includes an electrode 116 in the same layer as the gate 106, an electrode 117 in the same layer as the drain 109, and the third insulation layer 111 disposed between electrodes 116 and 117, and the storage capacitor is formed between the electrode 116 and the electrode 117.
The storage capacitor is a primary means to maintain the pixel electrode at a potential at the end of a scan signal of a TFT LCD pixel, and the storage capacitor of the pixel can be added uniformly to improve the uniformity of a picture effectively. However the storage capacitor of the pixel has to be added with the consequence that the aperture ratio is smaller in the prior art.